A camshaft adjuster of the type mentioned at the outset is known from DE 10 2012 203 114 A1, for example. This unexamined patent application describes a camshaft adjusting device for an internal combustion engine of a motor vehicle, including a drive part, such as an outer rotor, and an output part, such as an inner rotor, the output part being mounted rotatably relative to the drive part between a first angular position and a second angular position, furthermore an insert part, which originally is separate from the drive part and the output part, being situated in a rotation angle limiting gate formed in the drive part or the output part, the insert part being situated so as to make blocking contact with two axially movable blocking elements, such as pins or journals. This unexamined patent application furthermore also describes a timing drive including such a camshaft adjusting device, and an internal combustion engine including such a timing drive.
Gas exchange valves of internal combustion engines may be actuated by lobes of a camshaft. The opening and closing times of the gas exchange valves may be deliberately established via the arrangement and shape of the lobes. The camshaft is usually actuated, driven and/or controlled by the crankshaft of the internal combustion engine. The opening and closing points in time of the gas exchange valves of the internal combustion engine are usually predefined by a relative rotational position or phase position or angular position between the lobes and the crankshaft. A variable adjustment of the opening and closing points in time of the gas exchange valves may be achieved by a relative change of this relative rotational position between the camshaft and the crankshaft. With the aid of the variable adjustment of the opening and closing points in time of the gas exchange valves, it is possible, as a function of the instantaneous operating state of the internal combustion engine, to positively influence the emission characteristics, for example, to lower the fuel consumption, to increase the efficiency and/or to increase the maximum torque and/or the maximum power of the internal combustion engine.
This variable adjustment of the opening and closing points in time of the gas exchange valves may be carried out or made possible by a camshaft adjusting device, or such a camshaft adjuster, provided between the crankshaft and the camshaft.
For this purpose, conventionally a camshaft adjuster is provided in the kinematic chain between the crankshaft and the camshaft. One part of the camshaft adjuster, which hereafter is referred to as the stator, is connected preferably non-rotatably to the crankshaft. Another part of the camshaft adjuster, which hereafter is referred to as the rotor, is connected preferably non-rotatably to the camshaft. Conventionally, a gear is provided between the stator and the rotor. In a hydraulic camshaft adjuster of the vane cell type, this gear is usually provided in the form of a hydraulically actuated vane cell, or a plurality thereof. By applying hydraulic pressure to the vane cell, it is possible, for example with the aid of a control unit and/or valves, to achieve the variable adjustment of the opening and closing points in time of the gas exchange valves. This embodiment may also be referred to as a rotary piston adjuster.
It is possible for operating states to occur in a hydraulic camshaft adjuster during which this hydraulic actuation or hydraulic control is not possible or not ensured or not economical or not desirable. For example, the rotational position is usually not hydraulically predefined during a starting process of the internal combustion engine. An uncontrolled rotational position or an uncontrolled change of the rotational position may cause, for example, increased wear of the camshaft adjuster, of the camshaft, of the gas exchange valves, or in general of the internal combustion engine. To avoid the uncontrolled rotational position or the uncontrolled change of the rotational position, a releasable or liftable locking of the rotor to the stator is desired. Based on the rotational position of the gas exchange valves, “early” locking, “intermediate” locking or “late” locking may be desired. These are referred to as advance position, intermediate position, retard position, advance locking, intermediate locking, retard locking or the like.
For this purpose, it is known from the prior art mentioned at the outset to provide a blocking element, such as a bolt, a peg or a pin. The blocking element may be accommodated or mounted or attached in the rotor, for example. The blocking element may be actuated by a spring preload, for example. The blocking element may be hydraulically released or lifted, for example. The blocking element may make contact with a locking gate of the stator, for example. For example, the locking gate may be provided in one piece in the stator, or may, for example, be designed as an insert part. When differing requirements exist with regard to the gate and the part accommodating the gate, for example with respect to the hardness, it is advantageous if the locking gate is formed by an insert part.
Such insert parts may be inserted during assembly, for example when a clearance fit is present, or may be pressed in, for example when an interference fit is present. Insertion with a clearance fit offers the advantage that the assembly is easy to be carried out. A clearance fit, however, has the disadvantage during operation that noise development and/or clearance-induced wear may occur. An interference fit has the disadvantage during assembly that mechanical overdeterminations, for example due to complex component geometries, are not economically preventable. An interference fit, however, has the advantage during operation that noise development and/or clearance-induced wear may be prevented.